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<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<!-- <h1>使用 let 声明变量</h1>
		<p id="demo"></p>
		<script>
			var x = 10;
			{
				let x = 2;
			}
			document.getElementById("demo").innerHTML = x;
		</script> -->
		
		<!-- <h1>Math.pow()</h1>
		<p id="demo"></p>
		<script type="text/javascript">
			var x=5;
			document.getElementById("demo").innerHTML=Math.pow(x,2);
		</script> -->
		
		<!-- <h1>JavaScript Array.find()</h1>
		<p id="demo"></p>
		<script type="text/javascript">
			var numbers=[4,6,9,16,25,36,45];
			var first=numbers.find(myFunction);
			
			document.getElementById("demo").innerHTML = "大于 18 的第一个值是：" + first;
			function myFunction(value,index,array){
				return value>18;
			}
		</script> -->
		
		<h1>JavaScript 箭头函数</h1>
		<p id="demo"></p>
		<script type="text/javascript">
			const x=(x,y)=>x*y;
			document.getElementById("demo").innerHTML = x(5, 5);
		</script>
	</body>
</html>
